topic.9. powerpoint.9.3

Question 1

Describe blood flow using these terms arteries, arterioles, veins, venules and capillaries

Answer 1

They are all blood vessels that make up the circulatory system.
Arteries-arterioles-capillaries-venules-veins
capillaries: exchange material with interstitial fluid

Question 2

Describe the 3 layers of the walls of arteries

Answer 2

inner: endothelial cells
middle: smooth muscle
outer: elastic fibers; made up of elastin, which is a protein found in connective tissue.

Question 3

What controls the amount of flow and pressure of blood that enters capillaries?

Answer 3

arterioles

Question 4

T/F
1) Arteries have low resistance to flow
2)Arteries have thick walls

Answer 4

True because they have large diameters
True: to withstand high pressure

Question 5

Explain why the pressure never drops to zero in arteries?

Answer 5

A process called elasticity:
Blood flows out from the heart, stretches the arteries, and stores PE. PE is released when ventricles relax, causing the artery wall to recoil. This rebounding action helps maintain blood flow even while the ventricle is relaxing, preventing the pressure from dropping to zero between heartbeats.

Question 6

What is the difference in structure between arteries and capillaries?

Answer 6

Capillaries unlike arteries have…
-thin wall, single endothelial layer
-no smooth muscle
-large SA

Question 7

How is contraction controlled in capillaries and arterioles?

Answer 7

arterioles: smooth muscle
-low O2 and high CO2 in tissue, smooth muscle dilates, increasing diameter of
arterioles and allowing more blood flow

Capillaries: precapillary sphincters
is a band of smooth muscle that can contract and close the branches off to blood flow

Question 8

Capillaries involve an exchange of material with interstitial fluid. Having said so, do we expect a faster or slower rate of blood flow than arteries and veins?

Answer 8

Slower, maximizes time for exchange of material

Question 9

Two major mechanisms drive exchange of substances

Answer 9

We are talking about capillaries:
-bulk flow: movement of material in/out of capillaries according to pressure differences.
-diffusion along concentration gradient
O2, CO2 can passively move across the walls of capillaries based on their concentration differences.

Question 10

Capillaries have ___ and ___ that allow water-soluble substances to diffuse from capillaries to interstitial fluid

Answer 10

-fused vesicle channels (membrane-bound sacs)
-intercellular clefts (b/n endothelial cells 1& 2)

Question 11

How does hydrostatic pressure relate to capillaries?

Answer 11

Hydrostatic pressure is the pressure of the blood, when it’s higher than interstitial fluid pressure at the point where arterioles meet capillaries(ateriole end of capillaries), forces water and small solutes into the venous end of capillaries

Question 12

The fluids leave the capillaries at the arterial end because…

Answer 12

the net filtration pressure of the blood is higher at the arterial end than it is at the venous end.

Question 13

The fluids reenter the capillaries at the venous end because…

Answer 13

the net filtration pressure of the interstitial fluid is higher than hydrostaic pressure at the venous end than it is at the arterial end.
***fluid constantly leaking out and being pulled back in, thus helping to
distribute fluid

Question 14

Starling forces

Answer 14

net filtration pressure affect the distribution of fluid across the capillary, because fluid constantly leaking out and being pulled back in, thus helping to
distribute fluid

Question 15

is interstitial fluid considered tissue?

Answer 15

yes

Question 16

Whether fluid will move out of or into a capillary depends on

Answer 16

1. net filtration pressure, hydrostatic pressure of blood in capillaries minus hydrostatic pressure of interstitial fluid outside capillaries
   2)oncotic pressure aka osmotic pressure

Question 17

solutes are generally the same in __ and __

Answer 17

tissue(interstitual fluid) and plasma(in capillaries)

Question 18

___is greater than protein
concentration of interstitial fluid

Answer 18

protein concentration of plasma;
because plasma proteins are too large to pass through the pores in the capillary walls, restricting their filtration into the interstitial fluid. As a result, the protein concentration in the plasma remains higher than in the interstitial fluid.

Question 19

What is colloid osmotic pressure?

Answer 19

colloid osmotic pressure is the pressure that wants to draw interstitial fluid out of the capillaries.
mechanism: A higher concentration of plasma proteins in blood plasma creates a higher osmotic pressure.

Question 20

What is oncotic pressure?

Answer 20

is the pressure that wants to draw interstitial fluid into the capillary through osmosis.

Question 21

Colloid osmotic pressure is greater in the ___than in the___

Answer 21

plasma, interstitial fluid

Question 22

What is the equation to calculate distribution of fluid across capillary wall?

Answer 22

(Pc+πi)- (Pi+πp)
fluid out -fluid in
Pc-hydrostatic pressure in capillary
πi: colloid osmotic pressure of interstitial fluid
Pi: hydrostaic pressure of interstiual fluid
πp: colloid osmotic pressure of blood plasma

Question 23

In this equation, what can we expect to always be zero?
(Pc+πi)- (Pi+πp)

Answer 23

πi: colloid osmotic pressure of interstitial fluid
Because there are no plasma proteins in interstitial fluid and thus it creates no pressure

Question 24

Lymphatic system

Answer 24

Key component of the immune system
-Extensive network of vessels that collects excess interstitial fluid (becomes lymph), filters and returns it to the venous blood

Question 25

What are the tissues and organic involved in the lympathic system?

Answer 25

Lymph nodes, spleen, thymus, tonsils

Question 26

Blood moves through veins in
response to _____.
A. Relatively high pressure in the veins caused by blood
leaving the capillaries
B. Contraction of smooth muscle in the walls of the veins
C. Contraction of the valves in the veins
D. Contraction of skeletal muscles surrounding the veins

Answer 26

B. Contraction of smooth muscle in the walls of the veins
D. Contraction of skeletal muscles surrounding the veins**

explain: When skeletal muscles contract, they compress nearby veins, increasing the internal pressure of the vein; pushing the blood foward

explained:Contractions of the smooth muscles in the walls of veins,
decreases the diameter of the vein, creating more pressure and
aiding in the movement of blood.

Question 27

t/F veins have reservoirs

Answer 27

true

Question 28

What is a key difference between arteries and veins?

Answer 28

Veins have one-way valves that prevent blood from flowing backward
Explain: skeletal muscle contract, compress nearby veins and increases internal of vein pushing blood forward, when muscle relaxes the valve closes to prevent backword flow of blood

Question 29

What is the role of Nitric oxide and Endothelin in relation to blood flow?

Answer 29

Nitric oxide is a major inducer of vasodilation
Endothelin: is a peptide, and major inducer of vasoconstriction

Question 30

t/f blood pressure in arteries is lower than in veins

Answer 30

false
veins have thinner walls and not as elastic

Question 31

Arterioles are under what type of control?

Answer 31

local: meets needs of a particular tissue
central(extrinsic) control: meets the needs of the whole body

Question 32

Active hyperemia uses what type of control?

Answer 32

Local control-
active hyperemia, there is an increase in the metabolism of the tissue. Low O2 and high Co2.
Oxygen is used faster so arterioles are dilating to achieve enough blood flow.

Question 33

What type of control if flow autoregulation?

Answer 33

local control: response to a drop in blood pressure. Oxygen is depleted causing bp to drop so the arteriole responds by dilating and the flow will be restored.

Question 34

an example of extrinsic control

Answer 34

Effects of sympathetic nerves and plasma epinephrine on arterioles in skeletal muscles
Vasoconstriction/vasodilation/epinephrine/norepinephrine
*epinephrine can act as both

Question 35

How does vasoconstriction look in arteries vs veins?

Answer 35

Vasoconstriction in arteries reduces forward flow thru the circuit; vasoconstriction of veins increases forward flow